Experimental Study on the Dynamic Strength of Collision Barrier in Nuclear Ship
Pages 113-123
Details
Pages 113-123
The conventional idea to protect a nuclear ship from collision is that her collision barrier has ability to absorb kinetic energy of the colliding ship by being destroyed during collision. However recently Gessellshaft fur Kernergiever wertung in Schiffbau und Schiffahrt m.b.H. (GKSS) of Germany was said to have developed the new type of collision barrier in nuclear ship, which had impact strength sufficient to destroy a colliding ship without damage itself. In Japan research on the new type of barrier, as the above mentioned one, began to be made experimentally and theoretically about five years ago. This research did not include investigation into the dynamic effect on strength caused by collision. This paper deals with the dropping collision tests to be carried out in order to study the effect of impact load on strength, by comparing the results of the dropping tests with the ones obtained from the quasi-static collision tests. The same bow models and collision models were used in the both dropping and quasi-static collision tests. The main conclusion are as follows: l) It was found from the collision tests, in which the same bow models collided against the conventional energy-absorbed barrier model and the newly developed one respectively, that; (i) The former model's deflection was larger than the latter's one. (ii) Acceleration occured at the former model is smaller than one at the latter model. (iii) Impact load measured at the former model was smaller and its period was longer than the latter model's one. 2) The same collapse mode was observed in the both dropping tests. This fact gives assurance that it is unnecessary to take into account of velocity of stress wave in the collision analysis of ship. 3) Measured impact load in the dropping test was larger than static load in the quasi-static collision test when models were deflected largely. This is supposed to be caused by the effect of strain rate which raises the yield point of steel.
